This study is evaluating the clinical performance of a small particle bimodally filled hybrid proprietary composite resin and a dentin bonding system. This composite resin system is being employed for the restoration of class II carious lesions in posterior teeth. Its performance will be compared to that of a conventional amalgam. Fifty restorations of each of the two materials will constitute the study. Each restoration will be evaluated for clinical performance using a standardized method. Also, an attempt is being made to quantify any loss of material due to surface disintegration or wear using a recently developed scale and device.